Rotary kiln for burning cement, ore, and similar materials



L. D. PARKER Feb. 3, 1931.

ROTARY K ILN FOR BURNING CEMENT, ORE, AND SIMILAR MATERIALS 2 Sheets-Sheet 1 Filed Sept. 9, 1926 Feb. 3, 1931. V L. D. PARKER 1,791,232

ROTARY KILN FOR BURNING CEMENT, ORE AND SIMILAR MATERIALS- Filed Sept. 9, 1926 2 Sheets-Sheet 2 M OM Z-CLL l atented Feb. 3, 1931 A 'tti r me LIONEL nonenas PARKER, or nannoiv-rn-ronnnss, ENGLAND, Ass'reNon T0 vrexnns QLIMrrED, or LONDON, ENGLAND, annrrrsn COMPANY I ROTARY KILN ron BURNING CEMENT, ORE,.AND s MiLAn MATERIALS Ap lication filed September 9,4926, Serial No 134,344, and in Gran Britain September 12,1925. r

This invention'relates to rotary kilns for burning cement, ore and similar materials, of

the kind provided with a heat recuperator forming a prolongation of the kiln and rotating therewith, air for supporting combustion within the kiln travelling through the recuperator in contact with the hot material or clinker that is being discharged through the recuperator so that 'anuintercha'n'ge of heat takes place resulting in the partial cool- According to the present'invention the 'recuperator comprises a hollow member or cyllnder forming an extension of the kiln shell, and

a number of tubes or conduitsarranged around this cylinder and suitably attached thereto wlth the rear ends open to the atmosphere for the entry of air and the exit of the hot material and with the front ends,

in communication with the front part of the cylinder for the entry of the hot material which passes by gravity through the tubes in the opposite direction to the flow of air therethrough, the said'tubes being so con structed and arranged that the outer part-of each tube when it reaches a position below the cylinder during the rotation of, the kiln, constitutes an inclined surface down which 7 the material. moves by gravity. The front ends of the tubes'may communicate with the interior of the frontportion of the cylinder by means of curved hollow members, and the rear end of eachtube may be provided with a hood or'plate so formed as to prevent the hot material from passing out of the tube when it reaches a position above the cylinder. The said tubes may be tapered with the small ends situated at the front, or they may be cylindrical and arranged with their axis at an inclination to the axis of the kiln.

In order that the said invention may be clearly understood and readily carried into effect, the same will now be described more fully with reference to, the accompanying drawings, in which- Figure 1 is a sectional side elevation. showing a constructional. form ofrecuperator according to this invention,

Figure 2 is a section taken approximately on the line 2,2 of Figure 1 and viewed from the right of the'latter figure and,

Figure 3 is a section in two planes taken approximately onthe line ,3, 3 of Figure 1 and viewed from the left of the latter figure. A is the discharge end of the kiln proper which is inclined slightly to the horizontal end of the kiln is lined'with fire brick Z) and" the remainder may be lined with renewable Wearing plates to which are attached a numher of lifters Z2 b for cascading the hot material through the entering air to whichit imparts heat. Around the outside of the cylinder are the aforesaid tapered tubes C, C =(for' example six equally spaced) lifters G C of channel or othersuitable section. The smaller. ends of thesaid tapered tubes are connected to a forward extension B of the cylinder B by hollow curved members C by which communication is established between the interiors of the'tu-bes and the interior of the said extension vhile the larger ends of the said tubes point towards the rear or feed end of the kiln. The said tubes are also attached to the cylinder B by braced members C (see Figure 2) and the means of attachment to this central cylinder and to the extension B are such that the said tubes can-readily be removed if required for repair or renewal. The axes of the tapered tubes may be parallel or approx imatelyparallel tothe axis of the kiln as:

shown and the angle of the taper of thesaid tubes may be slightly greater than the angle of inclination of the kiln, so that the material inthe said tubes travels by gravitythere through from the smaller ends to the larger ends. The kiln and the re'cuperator rotatetogether and the front end of the extension B which may belined with renewable 'wearingplates and fitted with longltudinal of the cylinder may be closed by means of a door or hood B through the centre of which the usual firing pipe B projects. The extension B of the cylinder can be supported by a ring B and rollers 5 I) as is well understood and the front end of the kiln is similarly supported, the ring on the kiln being shown at A but the rollers being omitted. The larger ends of the tubes C are provided with hoods or plates C which close the inner portions of the larger ends of the tubes (i. e. those portions nearestthe cylinder B) and thereby prevent the hot material from passing out of the tubes when they are above the kiln, but leave openings for the exit ofthe hot material when each tube reaches its lowermost position. The tapered tubes may be enclosed by a more or less cylindrical casing C.

When the kiln is rotating the clinker or other hot material after leaving the burning zone enters the cylinder B where it is lifted and cascaded through the incoming air by the aforesaid lifters 6 The said mate-rial then passes into the extension B and thence falls through the. curved members C into the smaller ends of the tapered tubes In these tubes the material is further cascaded by the aforesaid longitudinal lifters C so that it is brought into thorough contact with the air which enters at the larger ends of the tubes, the material passing by gravity towards the said larger ends as aforesaid untilit is discharged at a position adjacent to the point where the cylinder B joins the kiln proper. As the incoming air moves in the opposite direction to the hot material, heat is imparted to the air and the material is cooled.

By reason of this invention a more effective recuperating action is obtained than has heretofore been possible with recuperators forming a prolongation of the kiln, owing to the fact that the hot material first passes through the cylinder B and then in a reverse direction through the tapered tubes C The arrangement of these tubes is also such that the material travels by gravity therethrough without the necessity of employing inclined blades or screw lifters, thus avoiding obstructional surfaces and restriction of the incoming air and also avoiding the heavy wearto which the screw lifters .are subjected,

this wear necessitating frequent stoppages for renewal purposes. The air entering the recuperator on its way to the kiln is not throttled by having to pass through a chute as is the case in the well known separate rotary cooler, but on the contrary the velocity of the incoming air is reduced owing to the large capacity of the extension B and enters the cylinder B at a relatively low velocity, thus enabling it to remove more heat from the burned material. Furthermore the whole, of the wearing plates of the recuperator are easily accessible and removable and if neces- 'kiln shell in front of the burning zone of the kiln, a number of conduits arranged around sa d hollow member and attached thereto with their rear ends open to the atmosphere forthe entry" of air and 'the'eXit of the hot material and with their frontends in cominunication'with the front part ofsaid hollow member, and a portion of each of said 'co nduits so situated that it forms an inclined surface down which the material moves by gravity and flows out of therear open end as eachconduit reaches a position below said hollow member.

V 2. In a rotary kiln,the combinationwith the elements claimed in claim 1 of a member arranged transversely of and at the rear end of each conduit and closing that portion of its end nearest the ZLXlS of the hollow member to prevent the hot material from passing out of the conduits when they reach positions above the hollow member,

In a rotary kiln the combination of a hollow member forming an extension of the kiln shell in front of the burning zone of the kiln, a number of tapered tubes arranged around said hollow member and attached thereto with their larger rear ends open to the atmosphere forthe entry of air and the exit of thehot material and with their smaller front ends in communication with the front part of said hollow member, the outer part of each of said tapered tubes forming an inclined surface down which thematerial moves by gravity and flows out of the rear open end as each tube reaches a position below said hollow member. Y I

' 4. In a rotary kiln, the combination with the elements claimed in claim 3, of a member arranged transversely of and at the rear end ofeach tube and closing that portion of its end nearest the axis of the hollow member to preyent the hot material from passing out of the tubes when they reach positions above the hollow member;

LIONEL DOUGLAS PARKER. 

